Here is some "cast iron" that may mystify those of you in N America. I have never met anyone from N America who knows of these disc harrow carrier wheel bogies. Over here they were quite commonly bought as an optional extra to a set of trailing, tractor drawn, Massey-Harris disc harrows when the farmer had a need to travel down roads with them.
Each gang of a four gang disc harrow needed one of these bogies to carry it along the road. I well remember my grandfather having a set and we kids used to charge around the yard with one each for a bit of fun. These are the only set I have seen since those far off childhood days. I bought them from a farm sale about ten years ago against stiff opposition from a stationary engine collector who wanted the wheels for making engine trolleys. The vandal!!!! Each wheel is stamped M-H.
Using them was simple. Just place the long arm under the middle rear of a gang with the hook locating onto the disc axle. (Hook just visible on the left hand bogie). Then pull the front of the arm up by the chain so that it lifts the gang, then hitch the chain up to the frame of the implement so that the axle does not drop to the floor. Very effective but not for racing along the road with even so!